Evolution Of Thermal Sensitivity Research Articles

Evolution of Thermal Sensitivity in Changing and Variable Climates

Evolutionary adaptation to temperature and climate depends on both the extent to which organisms experience spatial and temporal environmental variation (exposure) and how responsive they are to the environmental variation (sensitivity). Theoretical models and experiments suggesting substantial potential for thermal adaptation have largely omitted realistic environmental variation. Environmental variation can drive fluctuations in selection that slow adaptive evolution. We review how carefully filtering environmental conditions based on how organisms experience their environment and further considering organismal sensitivity can improve predictions of thermal adaptation. We contrast taxa differing in exposure and sensitivity. Plasticity can increase the rate of evolutionary adaptation in taxa exposed to pronounced environmental variation. However, forms of plasticity that severely limit exposure, such as behavioral thermoregulation and phenological shifts, can hinder thermal adaptation. Despite examples of rapid thermal adaptation, experimental studies often reveal evolutionary constraints. Further investigating these constraints and issues of timescale and thermal history are needed to predict evolutionary adaptation and, consequently, population persistence in changing and variable environments.

Thermal acclimation of swimming performance in newt larvae: the influence of diel temperature fluctuations during embryogenesis

Summary1. Thermal acclimation is one of the basic strategies by which organisms cope with thermal heterogeneity of the environment. Under predictable variation in environmental temperatures, theory predicts that selection favours acclimation of thermal performance curves over fixed phenotypes.2. We examined the influence of diel fluctuations in developmental temperatures on the thermal sensitivity of the maximal swimming capacity in larvae of the alpine newt,Triturus alpestris.3. We incubated newt eggs under three thermal regimes with varying daily amplitudes (1, 5 and 9 °C) and similar means (17·6–17·9 °C), and accordingly we measured the swimming speed of hatched larvae at three experimental temperatures (12, 17 and 22 °C), which they would normally experience in their natural habitat.4. Embryonic development under low and middle temperature fluctuations produced larvae with similar swimming speeds across experimental temperatures. In contrast, the most fluctuating regime induced development of phenotypes, which at 12 °C swam faster than larvae developed under moderate diel fluctuations.5. Our results provide evidence that diel temperature fluctuations induce acclimation of thermal dependence of locomotor performance. In ectotherms experiencing diel cycles in environmental temperatures, this plastic response may act as an important pacemaker in the evolution of thermal sensitivity.

Constraints on the Evolution of Thermal Sensitivity of Foraging in Trichogramma: Genetic Trade-Offs and Plasticity in Maternal Selection

Constraints on the Evolution of Thermal Sensitivity of Foraging in Trichogramma: Genetic Trade-Offs and Plasticity in Maternal Selection